Amusement park visitors had to be rescued by firefighters after they became trapped on a stalled roller coaster 100 feet up in the air.
Two dozen people were trapped for nearly four hours on the Joker's Jinx ride at Six Flags America, in Maryland, on Thursday.
Prince George's County Fire/EMS spokesman Mark Brady said on his Twitter account that the riders came to a standstill at about 5.30pm.
A spokesperson for the park said in a statement: 'Joker's Jinx did not complete its regular ride cycle, causing it to stop at a safe location on the track.'
The riders, the youngest being nine and ten, were upright when the roller coaster stalled.
Ten passengers were brought down in a cherry picker by about 8.15pm with the rest all being on the ground by 9.20pm.
Footage of the incident showed firefighters in a rescue bucket talking with the passengers, none of whom appeared to be in distress, Brady said.
Javier Valverde was waiting on the ground as his children Julia, 15, and Desidariaus, 13, were stuck on the ride.
'You're worried for them because you can't go save them,' He told NBC Washington. 'If there was a ladder, I would have gone up the ladder if I could.'
When he was finally reunited with his children Mr Valverde said he felt 'very, very thankful'.
Six Flags' website describes the Joker's Jinx as having a 'spaghetti bowl' design, with the roller coaster doing 'a cobra roll, a sidewinder loop, a corkscrew, and countless swift reversals'.
Six Flags America said: 'The safety of our guests is our highest priority and the ride will be closed for a thorough inspection before reopening.'
This is not the first time passengers have been trapped on the Joker's Jinx ride.
In August 2014 two dozen passengers became stuck, some for as long as five hours.
A judge later ordered the park to pay one family $60,000 - $10,000 for each family member on the ride.